The field of this invention relates to optical drop detecting systems. More specifically this invention relates to optical drop detecting systems which produce an electrical signal in response to a drop falling through a translucent drip chamber.
Optical drop detecting systems are commonly used with intravenous fluid administration equipment and enteral feeding apparatus. These optical drop detecting systems normally include a translucent drip chamber on which is mounted optical sensing apparatus. Optical sensing of the passage of a drop through the translucent drip chamber is typically performed by the interruption of a light beam by the falling drop. To accomplish this optical sensing a light source and receiver are positioned on either side of the translucent drip chamber. When the light beam produced by the light source is interrupted by the falling drop an electrical pulse is transmitted to recording equipment by the receiver. If the drop size is known the volume and flow rate of the monitored fluid can be measured by recording and counting the falling drops.
Problems have arisen in the operation of drop detecting systems when the optical sensing equipment is used in an environment with changing levels of ambient light. In such situations light receivers may become flooded with light and will not be able to detect the interruption of the light beam by the falling of the drop. Additionally, flashes or intermittent periods of darkness may trigger the same response as a falling drop. Such changing ambient light conditions may be present in a hospital room if the drop detecting system is located near a window or a lamp. The consequence of the recording of false signals will be improper and inaccurate administration of I.V. fluid or enteral feeding solutions to the patient.
Another problem for conventional drop detecting systems occurs when the drip chamber is inadvertently tilted from a vertical axis. This tilting of the drip chamber will cause the falling drops to land on one side of the drip chamber and possibly miss the optical sensing equipment entirely.
There is therefore a need in the art to provide a drop detecting system which is operable in a wide variety of constant or changing ambient light conditions. Additionally, there is also a need in the art to provide a drop detecting system that can be operated when the drip chamber is tilted from a vertical axis.
It is an advantage of the device of the present invention to provide a drop detecting system which is operable in a wide range of constant or changing ambient light conditions and is also operable whenever the drip chamber is tilted from a vertical axis.